Method of dehydrating and assembling refrigeration apparatus



May 1, 1951 s. c. EAKER METHOD OF DEHYDRATING AND ASSEMBLING REFRIGERATION APPARATUS Filed May 11, 1948 gy/yssgs: I \J. W, NM @ZM ATTORNEY INVENTOR S/DNEY 61 E'AKER Patented May 1, 1951 UNITED STATES ATENT OFFICE IVIETHQD F DEHYDRATING AND ASSEM- BLING REFRIGERATION APPARATUS Application May 11, 1948, Serial No. 26,325

14 Claims. 1 This invention relates to the manufacture of refrigeration apparatus and more especially to a method of dehydratin such apparatus.

When a drying agent, such as dehydrated calcium sulphate, silica gel and the like, is inserted in a refrigerating system, the sealing means sur-.

rounding such drying agent must be broken. thereby exposing the drying agent to the ambient air. When thus exposed, the drying agent absorbs moisture from the ambient air and loses some of its effectiveness before its insertion into the system is completed. The refrigerating system may also absorb moisture during this time if it has been dehydrated previously.

It is, accordingly, an object of the invention to provide a method for assembling refrigerating apparatus which method provides that the drying agent is in its most effective state after insertion in the refrigerating system.

It is a further object of the invention to provide a means for reactivating the drying agent in refrigerating apparatus after it has been installed therein.

These and other objects are eiiected by the invention as will be apparent from the following description and claims taken in connection with the accompanying drawings, forming a part of this application, in which:

Fig. l is a drawing of refrigerating apparatus assembled to the stage at which the dehydrating process of this invention may be effected, parts of the apparatus being shown in section;

Fig. 2 is an enlarged sectional view of the compressor cylinder of Fig. l and its valve chamber;

Fig. 3 is an enlarged sectional view of the capsule and the drying agent of Fig. 1; and

Fig. 4 is an enlarged sectional view of one end of the capsule of Fig. 3 but showing a modification of the capsule.

Referring to these drawings, the reference numeral iii designates a casing containing a compressor i2 and an electric motor it for driving the compressor iii. The casing it, the compressor i2, and the electric motor form a refrigerant compressing unit for a hermetically-sealed refrigerating system. The motor M comprises a housing l6 pressed into the casing iii and a stator i8 pressed into the housing it, The stator i8 is Wound with cotton covered wire 29 and also embodies other organic insulating material. The central portion of the housing it provides a hearing for the shaft 22 of the motor it which shaft overhangs the bearing at both ends. A rotor 24 is secured to one end of the shaft 22 and the other end of the shaft 22 carries a crank arm 26 which 2 actuates the connecting rod 23 and the piston 38 of the compressor l2.

The valve plates 32 and 34 of the compressor 12 comprise thin sheets of cold rolled steel in which tongues 38 and 38 are cut, the tongue 36 underlying the intake port it and the tongue 38 overlying the exhaust port e2 of the compressor. The valve tongues 36 and 38 are biased to close the ports 48 and 62 but open when gas pressure is exerted on them through the respective ports M3 and 32. The inlet to the intake port 48 consists of a short tube it which communicates with the interior of the casing ill at one side of the electric motor I l. An intake tube 46 to the casing H3 is located on the other side of the electric motor It.

A tube 68 connects the exhaust port of the compressor IE to a condenser 50 comprising a metal plate 52 and an undulating tube 54 brazed thereto. A second tube 56 provided with a hand valve 58 is connected to the tube 48.

A capsule to is secured at one of its ends to the lower end of the condenser tube 55. The other end of the capsule 5t connects with a capillary flow impeding tube 62 such as is commonly used in a refrigerating system to provide a pressure diiierential between the high pressure side and the low pressure side of said apparatus. The capsule contains a drying agent 64, dehydrated calcium sulphate, which is formed into a solid cylindrical block. A screen 66 is located in the capsule to in advance of the capillary tube 62 to prevent clogging of the latter.

The other end of the capillary tube 62 connects with a refrigerant evaporator 68 such as used in domestic refrigerators, and the evaporator (58 in turn is connected to a tube ill which will comprise the suction conduit when the refrigerating apparatus is completed.

When the capsule (it! with the drying agent 64 is brazed to the tubes 54 and 62, the seals (not shown) closing the openings of the capsule 60 are removed, and even though the drying agent 64 has been perfectly dehydrated at the time the capsule 6B was sealed, some moistur from the atmosphere will be absorbed by the drying agent (it before the brazing of the capsule 60 to the tubes 56 and 62 is completed.

Dehydration Process In the dehydration process of this invention the dehydrating agent 64 is dehydrated after its installation together with the entire apparatus. This dehydration process is efiected as follows: The entire apparatus shown in Fig. 1 is inserted into an oven heated to a temperature of 265 F., and an air hose is connected to the tube 46 to force dry air through the apparatus. The temperature of the oven is preferably as high as the materials in the refrigerating apparatus permit, the material most sensitive to heat being the organic insulating material of the electric motor. The air used for the dehydration process has been dried to a dew point of 8G F.

The air entering the apparatus through the tube 46 flows through the stator it. of the electric motor l4 and dehydrates the organic insulating material as well as all of the other materials in the casing 18. It, thereupon, flows through a port ?2 in the housing US, through the compressor con'ipartment of the casing It and through the tube 44 into the valve chamber of the compressor and lifts the valve tongues 25 and 38 from their seats. The dehydrated air then flows through the tube 48 and a major portion of this air escapes through the tube 56 and the valve 58 which has been partially closed to create a back pressure which forces some of the air through the condenser tube 5 5, the capsule til, the capillary tube 62, the evaporator 88 and the tube E0 to dehydrate these passages as well as to remove the moisture taken up by the drying agent 64 during its installation. The dehydration of the organic material of the motor requires a large amount of air, and for this reason some of the air is allowed to escape through the valve 58 because this large quantity of air would require too long a time to pass through the capillary tube 62. The dehydrating process is continued for eight hours.

After this period. of time, the refrigerating ap paratus is removed from the oven and the remaining operations and processes necessary to complete the refrigerating apparatus are preferably in such manner that a minimum of ambient air enters the passages of this apparatus. The preferred process is to inject the necessary lubricating oil through tube 56 and then bra-2e the tube to the tube 23. Therefter a charging vessel is connected to the tube 55 while the refrigerating apparatus is still hot, thereby sealing the interior of the apparatus from the ambient atmos; e The charging and evacuation apparatus may then as described in the patent application, Serial No. 31,849, filed on June 8, 1948, W. S. Reid, now abandoned.

Modifications It is preferred to connect the restricted vent opening such as the valve in the tube 58 to facilitate the subsequent charging of he a aratus by a char.,ing vessel. However, if otl er charging methods are used, the restricted opening may be placed anywhere in the passages subsequent to the motor Hi and prior to the capillary tube 52. For example, it may be placed in the wall of that portion of he casing it] which houses the compressor 62. Th vent opening may also be placed in the wall of the condo -ser tube or in the wall of the capsul as shown in Fig. i which shows a tube of small diameter i l inserted in the end. wall of the capsule Gil. This tube should be pinched off and brazed as soon as possible after the dehydrating recess. If des red, tie drying agent may be placed in the capsule SE) in its natural state and. the complete dehydration may be eifected by the process described above.

It will be apparent from the above that this invention provides a means for dehydrating the dryin agent in refrigerating apparatus together with the remainder of the apparatus.

While the invention has been shown in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof.

What I claim is:

1. The method of dehydrating refrigerating apparatus including a drying agent, said method comprising assembling a plurality of the elements of said apparatus including said drying agent in their operating relationship and then dehydrating said elements by raising them to an elevated temperature and blowing dry air therethrough and in contact with said drying agent.

2. The method defined in the immediately preceding claim wherein said elements include an electric motor and its casing, said motor and casing being adapted to form elements of a hermetically-sealed refrigerating apparatus.

3. The method of dehydrating refrigerating apparatus embodying a first passage containing an electric motor and a second passage containing a drying agent, said passages being connected in series, said method comprising heating said passages and while hot passing a dry gas therethrough and in contact with said drying agent.

4. The method of dehydrating refrigerating apparatus embodying a first passage containing an electric motor and a second passage containing a drying agent, said passages being connected in series, said method comprising heating said passages while hot, passing a dry gas therethrough and in contact with said drying agent,

and thereafter sealing said passages from the ambient atmosphere while said passages are still hot.

5. The method defined in the immediate preceding claim wherein said drying agent consists of calcium sulphate.

6. The method of dehydrating and assembling refrigerating apparatus, said apparatus comprising a casing having an inlet, a compressor in said casing, said compressor having an exhaust port and an inlet port, said inlet port communicating with the interior of said casing, an electric motor in said casing for driving said compressor, a condenser having an inlet and an outlet, said inlet being connected to the exhaust port of said compressor, a capsule having an inlet and an outlet, said capsule inlet being connected to said condenser outlet and a drying agent exposed within said capsuie, said method comprising heating said apparatus and forcing a dry gas into the inlet of said casing while said apparatus is hot, at least some of said gas passing over said drying agent and issuing from the outlet of said condenser, and thereafter completing the assembly of the refrigerating apparatus.

'7. The method of dehydrating refrigerating apparatus, said apparatus comprisin a casing having an inlet, a compressor in said casing, said compressor having spring loaded valves, an exhaust port, and an inlet port, said inlet port communicating with the interior of said casing, an electric motor in said casing for driving said compressor, said casing inlet and said inlet port being on opposite sides of said motor, a condenser having an inlet and an outlet, said inlet being connected to the exhaust port of said compressor, a capsule having an inlet and an outlet, said capsule inlet being connected to said condenser outlet, and a drying agent exposed within said capsule and located between the inlet and the outlet thereof, said method comprising heating said apparatus and forcing dry gas into the inlet of said casing while said apparatus is hot, at least some of said gas passing through the valves of said compressor, over said dryin agent, and issues from the outlet of said capsule, and thereafter sealing the interior of said casing, condenser, and capsule from the ambient air While said casing, condenser, and capsule are still hot.

8. The method of dehydrating and assembling refrigerating apparatus, said apparatus comprising a casing having an inlet, a compressor in said casing, said compressor having an exhaust port, and an inlet port, said inlet port communicating with the interior of said casing, spring loaded valves for said ports, an electric motor in said casing for driving said compressor, said motor being located between said casing inlet and the intake port of said compressor, a condenser having an inlet and an outlet, said inlet being connected to the exhaust port of said compressor, a restricted venting opening located in said apparatus between said casing and said condenser, a capsule having an inlet and an outlet, said capsule inlet being connected to said condenser outlet and a drying agent in said capsule and located between the inlet and the outlet thereof, an evaporator having an inlet and an outlet, and a capillary impedance tube connecting the outlet of said capsule with the inlet of said evaporator, said method comprising heating said apparatus and forcing dry gas into the inlet of said casing while said apparatus is hot, at least some of said gas passing through the valves of said compressor, some of said gas issuing from said apparatus through said venting opening, and some of said gas passing over said drying agent and issuing from the outlet of said evaporator, thereafter inserting lubricating oil in said apparatus and thereafter sealing the interior of said apparatus from the ambient air while said apparatus is still hot.

9. The method of dehydrating and assembling refrigerating apparatus, said apparatus comprising a casing having an inlet, a compressor in said casing, said compressor having an exhaust port and an inlet port, said inlet port communicating with the interior of said casing, spring loaded valves for said ports, an electric motor in said casing for driving said compressor, said motor being located between said casing inlet and the intake port of said compressor, a condenser having an inlet and an outlet, said inlet being connected to the exhaust port of said compressor, a capsule having an inlet and an outlet, said capsule inlet being connected to said condenser outlet and a drying agent in said capsule and 6 located between the inlet and the outlet thereof, an evaporator having an inlet and an outlet, a capillary impedance tube connecting the outlet of said capsule with the inlet of said evaporator, and a restricted venting opening located in said apparatus between said motor and said capillary impedance tube, said method comprising heating said apparatus and forcing a dry gas into the inlet of said casing while said apparatus is hot, some of said gas issuing from said apparatus through said venting opening and some of said gas passing over said drying agent and issuing from the outlet of said evaporator, and there after inserting a lubricating oil in said apparatus and sealing the interior of said apparatus from the ambient air while said apparatus is still hot.

10. The method defined in the immediate preceding claim wherein said dryer consists of calcium sulphate.

11. The method of dehydrating refrigerating apparatus embodying a first passage containing an electric motor comprising organic material and a second passage containing calcium sulphate exposed to the air in said second passage, said passages being connected in series, said method comprising heating said passages to a temperature below that at which said organic material decomposes and while hot, passing a dry gas therethrough and in contact with said calcium sulphate, and thereafter sealing said passages from the ambient atmosphere while said passages are still hot.

12. The method of dehydrating refrigerating apparatus defined in claim 11 in which the passages are heated to a temperature of about 265 F.

13. The method of dehydrating refrigerating apparatus defined in claim 11 wherein the dry gas which is passed through the passages has a dew point temperature of about F.

14. The method of dehydrating refrigerating apparatus defined in claim 11 wherein the passages are heated to a temperature of about 265 F. and in which the dry gas which is passed through the passages has a dew point temperature of about 80 F.

SIDNEY C. EAKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,967,770 Ford July 24, 1934 2,260,608 Cormack Oct. 28, 1941 2,277,030 Anderson Mar. 24, 1942 2,430,692 Touborg Nov. 11, 1947 

1. THE METHOD OF DEHYDRATING REFRIGERATING APPARATUS INCLUDING A DRYING AGENT, SAID METHOD COMPRISING ASSEMBLING A PLURALITY OF THE ELEMENTS OF SAID APPARATUS INCLUDING SAID DRYING AGENT IN THEIR OPERATING RELATIONSHIP AND THEN DEHYDRATING SAID ELEMENTS BY RAISING THEM TO AN ELEVATED TEMPERATURE AND BLOWING DRY AIR THERETHROUGH AND IN CONTACT WITH SAID DRYING AGENT. 